Electroencephalogram & brain Waves

Electroencephalogram (EEG)

• 1.      The electrical activity of the brain and the cerebral cortex can be recorded through the instrument like electroencephalograph or cathode ray oscilloscope
• 2.      The recording of spontaneous electrical activity of the brain is electroencephalogram
• 3.      Electrical tracing of the cerebral cortex is called EEG
• 4.      Berger in 1929 was first to record EEG
• 5      Electroencephalic record in normal human subjects consist of four different types of rhythmic waves namely Alpha,Beta,Theta, & Delta etc
•  
• i.)                  Alpha Waves :- 10-12 cycles/sec. alpha waves are most prominent when the brain is under quite rest

-          Alpha waves disappear when eyes remain open

-          Alpha wave disappear entirely during sleep

ii.)                Beta wave :- 15-60 cycles/sec . beta waves appear during tension or during intense activities of CNS

iii.)              Theta wave :- 5-8 cycles/sec. theta wave are prominent in children between age of 2 to 5 years

iv.)              Delta waves :- 1-5 cycles /sec delta wave rarely found in normal adults during waking periods, but usually found during deep sleep

-          Delta waves in EEG also indicate brain damage